Leading the fight against Brome

Even the most intractable and costly grass weed problems can be overcome with the right management, the necessary determination and sufficient time.

Understanding, commitment and flexibility are the main keys to success.

 

 

Take a zero tolerance approach

Small patches of Brome should never be tolerated because the weed is so damaging and can spread so rapidly.

Headlands should be prioritised for regular inspection and control attention as brome almost invariably spreads from field margins.

Active management of headlands separately from the rest of the field is often the most cost-effective way of dealing with the weed.

Warning: Brome can appear without warning in almost any ground so careful identification and mapping is recommended each summer when the heads become clearly visible above the crop. Good record-keeping is important to allow historical hot-spots to be especially well-monitored.

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Maintain first-class field hygiene

Particular care should be taken to avoid importing Brome seeds into fields or spreading them from initial headland patches with combine harvesters and cultivation equipment. Contaminated seed, straw and manure also present clear infestation risks.

Infested areas of fields should always be harvested and cultivated last and machinery thoroughly cleaned before moving fields.

Wherever possible, cereal seed from infested areas should not be farm-saved and straw neither spread nor used for livestock bedding.

Warning: Brome seed can be moved up to 50 metres through harvesting and subsequent cultivation and is especially easily transported between fields and farms on machinery. Large amounts of viable later-maturing brome seed can be transported in straw.

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Match control measures to Brome species

Barren and Great Brome seeds should be shallow cultivated immediately after harvest to encourage germination for pre-planting glyphosate control, as exposure to light induces dormancy, increasing the likelihood of germination within the crop.

In contrast, later-maturing meadow, Rye and Great Brome seeds should be left on the surface for around a month before cultivating and pre-planting control, as burial will induce dormancy and seed survival.

The different Brome species also differ in their susceptibility to post-emergence herbicides, making species identification important in this respect too.

Warning: While Brome is easy to distinguish from other grass weeds, the five Brome species can be difficult to tell apart even once they have headed in the summer. Time should be taken to carefully identify the species present.

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Plough well or delay sowing

Ploughing – across the field or on headlands alone – to bury seed below the depth from which it is able to emerge can be very effective in controlling all Brome species.

Because Brome seeds are far less long-lived than Black-grass, Italian Rye-grass or Wild Oats in the soil, repeated ploughing in future years carries far less danger of bringing viable seeds back to the surface.

The relative lack of dormancy of Brome species means that delaying drilling – in the autumn or, even better, until the spring – to allow Brome germination and pre-planting control with Roundup can be very effective.

Warning: Ploughing needs to be of sufficient good quality soil inversion to consistently bury Brome seed to 15 cm. All emerged Brome plants must be destroyed before either autumn or spring drilling.

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Integrate cultural controls with the best herbicide programmes

Herbicide programmes must be based on a combination of pre- and post-emergence treatments as pre-em herbicides alone rarely give complete control.

Glyphosate is vital to remove all Brome growth before drilling, and where planting is delayed by more than a few days a permitted glyphosate is also recommended post-planting but pre-emergence of the crop.

Post-em wheat herbicides vary in their control of the different Brome species, Great Brome requiring especially robust strategies. There are no effective post-em products for Brome control in winter or spring barley.

Brome patches in crops should be rogued-out or sprayed-off with Roundup in May/early June to ensure no viable seed is set.

Warning: Being ALS inhibitors, all post-em Brome herbicides can only be used once in any programme. Since the ideal timing for Brome control may conflict with that for other grassweeds, particular care is essential in planning the treatment of mixed grass weed infestations.

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Prioritise Brome control across the rotation

Full advantage should be taken of every opportunity to control Bromes across the rotation.

Unless preceded by winter barley, pre-planting glyphosate control opportunities are limited in winter OSR, but a range of herbicides offer effective in-crop control.

Later sowing gives much more time for pre-planting control ahead of winter beans which also have good in-crop control options.

Spring crops offer the greatest pre-planting control opportunities – either in stubbles or through the use of cover crops effectively sprayed off ahead of drilling – while fallow breaks allow particularly good glyphosate control.

Warning: As Bromes quickly colonise bare patches in hedge bottoms or field margins, these are best planted with perennial grass-based mixtures. If necessary, mowing margins before March 1 and after July 31 (permitted under cross-compliance) gives reasonable Brome control, to limiting seed return.

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Identifying Anisantha species

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Sterile or Barren Brome (Bromus sterilis/Anisantha sterilis)

Wedge shaped spikelets with long, spreading awns, so are broader at the tips.

  • Ligules medium: 2-4mm long, pointed and deeply serrate
  • Length of spikelets, including the awns: 40 - 60mm
  • Length of awns: 15 - 35mm
  • Length of upper glume: 10 - 21mm
  • Main axis: Hairless or only minutely hairy

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Great Brome (Bromus diandrus/Anisantha diandra)

Wedge shaped spikelets with long, spreading awns, so are broader at the tips.

  • Ligules medium to large 3-6mm long, rounded and jagged
  • Length of spikelets, including the awns: 70 - 90mm
  • Length of awns: 30 - 60mm
  • Length of upper glume: 20 - 32mm
  • Main axis: Distinctly hairy (visible with naked eye)

Identifying Serrafalcus species

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Soft Brome (Bromus hordeaceus)

  • Ligules short 2mm long, blunt and toothed
  • Lower leaf sheaths: Hairy
  • Panicles: Usually compact
  • Length of panicle branches: Mainly shorter
  • Spikelets: Softly hairy usually
  • Length of spikelets, inc. the awns: 12-25mm long

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Meadow Brome (B. commutatus)

  • Ligules short to medium 1-4mm long, membranous, becoming torn
  • Lower leaf sheaths: Hairy
  • Panicles: Loose
  • Length of panicle branches: Mainly longer
  • Spikelets: Hairless usually
  • Length of spikelets, inc. the awns: 18-30mm long

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Rye Brome (B. secalinus)

  • Ligules short 1-2mm long, toothed
  • Lower leaf sheaths: Hairless or hairy
  • Panicles: Loose
  • Length of panicle branches: At least some longer
  • Spikelets: hairless or hairy
  • Length of spikelets, inc. the awns: 12-24mm long